1. Evidence of (definite) steatohepatitis on liver biopsy done within the previous 12 months with a NASH activity score of at least 4 (of a total possible score of 8) including a score of at least 1 each for steatosis, hepatocellular injury and parenchymal inflammation. Histological criteria of steatohepatitis include: (1) macrovesicular steatosis, (2) acinar zone 3 hepatocellular injury (ballooning degeneration), (3) parenchymal and (4) portal inflammation. Additionally helpful, but not required, features include the presence of (5) Mallory's hyaline and (6) pericellular and/or sinusoidal fibrosis that predominantly involves zone 3. If a liver biopsy is available within the last 12 months, then a repeat biopsy may not be conducted unless there has been a considerable change in body weight that may change liver histologic parameters associated with NASH